A 25-year review of fertilizer consumption and plant nutrient removal in the prairie provinces

Non-Peer ReviewedNutrient removal I replacement ratios were calculated in Manitoba, Saskatchewan, and Alberta from 1965 to 1989 by dividing total fertilizer (N, P, and K) sales by the total crop removal of plant nutrients. The nutrient removal I replacement ratios revealed that significant depletions of soil reserves of N, P, and K have taken place over the past 25 years. The average negative balance of N, P2O5, and K2O on the prairies is estimated at 640, 125, and 490 thousand tonnes. Even with the substantial increase in the use of fertilizers in the past five years compared to the 25 year average, the nutrient deficit continues to be unacceptably high for nitrogen (485,000 tonnes), only modest for phosphorus (86,000 tonnes), and as could be expected for potassium, has increased significantly to 570,000 tonnes. Overall, the calculations suggest that Manitoba is very close to nitrogen and phosphorus balance. Alberta has a relatively close balance, while Saskatchewan has not only experienced an unacceptably high N and P deficit for the past 25 years, but continues to do so at the present time

Large Scale Spectral Clustering Using Approximate Commute Time Embedding

Spectral clustering is a novel clustering method which can detect complex shapes of data clusters. However, it requires the eigen decomposition of the graph Laplacian matrix, which is proportion to $O(n^3)$ and thus is not suitable for large scale systems. Recently, many methods have been proposed to accelerate the computational time of spectral clustering. These approximate methods usually involve sampling techniques by which a lot information of the original data may be lost. In this work, we propose a fast and accurate spectral clustering approach using an approximate commute time embedding, which is similar to the spectral embedding. The method does not require using any sampling technique and computing any eigenvector at all. Instead it uses random projection and a linear time solver to find the approximate embedding. The experiments in several synthetic and real datasets show that the proposed approach has better clustering quality and is faster than the state-of-the-art approximate spectral clustering methods

Proteomic profiling of bovine M. longissimus lumborum from Crossbred Aberdeen Angus and Belgian Blue sired steers varying in genetic merit for carcass weight

Bovine skeletal muscle is a tissue of significant value to the beef industry and global economy. Proteomic analyses offer the opportunity to detect molecular mechanisms regulating muscle growth and intramuscular fat accumulation. The current study aimed to investigate differences in protein abundance in skeletal muscle tissue of cattle from two breeds of contrasting maturity (early vs. late maturing), adiposity, and muscle growth potential, namely, Belgian Blue (BB) × Holstein Friesian and Aberdeen Angus (AA) × Holstein Friesian. Twenty AA (n = 10) and BB (n = 10) sired steers, the progeny of sires of either high or low genetic merit, expressed as expected progeny difference for carcass weight (EPDcwt), and bred through AI, were evaluated as 4 genetic groups, BB-High, BB-Low, AA-High, and AA-Low (n = 5 per treatment). Chemical composition analysis of M. longissimus lumborum showed greater protein and moisture and decreased lipid concentrations for BB-sired compared with AA-sired steers. To investigate the effects of both sire breed and EPDcwt on M. longissimus lumborum, proteomic analysis was performed using 2-dimensional difference gel electrophoresis followed by mass spectrometry. Proteins were identified from their peptide sequences, using the National Center for Biotechnology Information (NCBI) and Swiss-prot databases. Metabolic enzymes involved in glycolysis (glycogen phosphorylase, phosphoglycerate mutase) and the citric acid cycle (aconitase 2, oxoglutarate dehydrogenase) were increased in AA- vs. BB-sired steers. Expression of proteins involved in cell structure, such as myosin light chain isoforms and troponins I and T, were also altered due to sire breed. Furthermore, heat shock protein β-1 and peroxiredoxin 6, involved in cell defense, had increased abundance in muscle of AA-sired relative to BB-sired steers. Protein abundance of glucose-6-phosphate isomerase, enolase-3, and pyruvate kinase was greater in AA-sired animals of High compared with Low EPDcwt. Changes in the expression of these proteins were supported by gene expression analysis using quantitative real-time PCR. This information will aid in our understanding of genetic infl uences controlling muscle growth and fat accumulation and could contribute to future breeding programs to increase lean tissue gain of beef cattle

Bovine tuberculosis in Northern Ireland : risk factors associated with time from post-outbreak test to subsequent herd breakdown

Compulsory bovine tuberculosis testing has been implemented since 1959 in NorthernIreland. Initial rapid progress in the eradication of the disease was followed by a situationwhere disease levels tended to fluctuate around a low level. This study explores recru-descence of bovine tuberculosis (bTB) in Northern Ireland herds by assessing risk factorsassociated with time from the six-month post-outbreak skin test until a further herd break-down. Bovine herds (n = 3377) were recruited in 2002 and 2003 and their survival analysedusing Kaplan–Meier survival estimates and a Cox proportional hazards model, with follow-up extending to August 2008. Exclusion criteria applied for study entry were bTB infection ina contiguous herd, changing of post restriction test to one of a higher risk status or chronicinfection. Chronic infection was defined as any situation where disclosure preceded thepost-outbreak test by two years or more. The application of these exclusion criteria meantthat herds recruited to the study were largely cleared of infection and not directly con-tiguous to other infected herds. Of the 3377 herds, 1402 (41.5%) suffered a further herdbreakdown before the end of follow-up. Median survival time was 582 days (interquartilerange = 336–1002 days). Breakdown severity (defined as the number of Single Intrader-mal Comparative Tuberculin Test (SICTT) reactors at disclosure test), local bTB prevalence,herd size and type were identified as significant risk factors (p 27.38 per year) of cattle. Consistent with other studies this workshows bTB confirmation to not be predictive of a future herd breakdown. This work showsbTB history as not being a risk factor for a future breakdown. This result could be reflectiveof the exclusion criteria used in the study, which may have selected for incidents wherehistorical status was of less importance.http://www.elsevier.com/locate/prevetmedhb201

Dynamics of ions in the selectivity filter of the KcsA channel

The statistical and dynamical properties of ions in the selectivity filter of the KcsA ion channel are considered on the basis of molecular dynamics (MD) simulations of the KcsA protein embedded in a lipid membrane surrounded by an ionic solution. A new approach to the derivation of a Brownian dynamics (BD) model of ion permeation through the filter is discussed, based on unbiased MD simulations. It is shown that depending on additional assumptions, ion’s dynamics can be described either by under-damped Langevin equation with constant damping and white noise or by Langevin equation with a fractional memory kernel. A comparison of the potential of the mean force derived from unbiased MD simulations with the potential produced by the umbrella sampling method demonstrates significant differences in these potentials. The origin of these differences is an open question that requires further clarifications

Random walk on the range of random walk

We study the random walk X on the range of a simple random walk on ℤ d in dimensions d≥4. When d≥5 we establish quenched and annealed scaling limits for the process X, which show that the intersections of the original simple random walk path are essentially unimportant. For d=4 our results are less precise, but we are able to show that any scaling limit for X will require logarithmic corrections to the polynomial scaling factors seen in higher dimensions. Furthermore, we demonstrate that when d=4 similar logarithmic corrections are necessary in describing the asymptotic behavior of the return probability of X to the origin

Denial at the top table: status attributions and implications for marketing

Senior marketing management is seldom represented on the Board of Directors nowadays, reflecting a deteriorating status of the marketing profession. We examine some of the key reasons for marketing’s demise, and discuss how the status of marketing may be restored by demonstrating the value of marketing to the business community. We attribute marketing’s demise to several related key factors: narrow typecasting, marginalisation and limited involvement in product development, questionable marketing curricula, insensitivity toward environmental change, questionable professional standards and roles, and marketing’s apparent lack of accountability to CEOs. Each of these leads to failure to communicate, create, or deliver value within marketing. We argue that a continued inability to deal with marketing’s crisis of representation will further erode the status of the discipline both academically and professionally

Thinking about growth : a cognitive mapping approach to understanding small business development

School of Managemen

Neutrino induced transitions between the ground states of the A=12 triad

Neutrino induced reactions on $^{12}$C, an ingredient of liquid scintillators, have been studied in several experiments. We show that for currently available neutrino energies, $E_{\nu} \le$ 300 MeV, calculated exclusive cross sections $^{12}$C$_{gs}(\nu,l)$$^{12}$N$_{gs}$ for both muon and electron neutrinos are essentially model independent, provided the calculations simultaneously describe the rates of several other reactions involving the same states or their isobar analogs. The calculations agree well with the measured cross sections, which can be therefore used to check the normalization of the incident neutrino spectrum and the efficiency of the detector.Comment: 9 pages REVTEX, 2 postscript figures, text and figures available at http://www.krl.caltech.edu/preprints/MAP.htm